How to make Blender use Python2.x?
In summary - you can't. 

Since Blender 2.5 we've moved on to Python 3.x This means it is not possible to use Python 2.x for scripting in Blender.

Now it's impossible to build against Python 2.x, and even if you did manage by editing the source-code, you'd probably run into problems running Blender, since Blender's own scripts are coded in Python 3.

Setting PYTHONPATH to a non Python 3.3 installation like Python 2.7 will cause Blender to crash and die horribly. (So always make sure you don't have PYTHONPATH set to a non-compatible Python version. But you can use it to point to an external Python 3.3 installation that has extra modules installed that don't come bundled with Blender).

Note: with current Blender pointing to Python 3.1 or Python 3.2 will also fail. So make always sure you point your PYTHONPATH to same version as used in Blender, should you need the external one.

In the long run you'll be better off getting used to Python 3. Also here is the proposal for the switch.